Ordinary removable dentures, dental plates and the like, comprise teeth mounted in a suitable plate or base. Denture adhesives or stabilizers are used to provide a cushion or gasket between the denture and the gums or tissues and to fill the interstices between the dentures and the gums or tissues.
Denture stabilizing or adhesive compositions can exhibit several deficiencies. Aesthetic deficiencies may include oozing of the adhesive from under the dental plate during insertion and throughout the wearing period and messiness and difficulty of removing the residual adhesive from the mouth and dentures. Additionally, food may become trapped between the denture and the oral cavity of the wearer. Considerable effort has been made over the years to develop denture adhesive compositions with improved holding capabilities which are aesthetically pleasing and easy to use. Both synthetic and natural polymers and gums have been used singly, in combination, and in combination with various adhesives and other materials in an attempt to lessen the deficiencies commonly associated with denture adhesive products.
Lower alkyl vinyl ether-maleic copolymers and salts thereof are known in the art for use in denture adhesive compositions. Such disclosures include: U.S. Pat. No. 3,003,988 to German et al., issued Oct. 10, 1961; U.S. Pat. No. 4,980,391 to Kumar et al., issued Dec. 25, 1990; U.S. Pat. No. 5,073,604 to Holeva et al., issued Dec. 17, 1991; and U.S. Pat. No. 5,525,652 to Clarke, issued Jun. 11, 1996. Layered denture adhesive compositions have also been disclosed in, for example, U.S. Pat. No. 4,880,702 to Homan et al., issued Nov. 14, 1989 and European Patent Application 0,353,375 to Altwirth, published Feb. 7, 1990. Despite the above-noted technologies, as well as others, a need still exists for denture stabilizing compositions providing improved hold and aethestics. Despite the above-noted technologies, as well as others, a need still exists for denture stabilizing compositions providing improved hold and aethestics.
In accordance with the present invention, it has been discovered that denture adhesive compositions comprising a non-adhesive self-supporting layer and ferric iron and divalent and/or monovalent metal partial salts of lower alkyl vinyl ether-maleic acid copolymers provide superior denture stability and retention over a significantly longer period of time versus conventional denture adhesives. Specifically, the compositions exhibit higher resistance to salivary washout while maintaining the same or better denture hold as conventional denture adhesives. This added resistance to salivary washout translates to longer denture hold and stability.
Therefore, it is an object of the present invention to provide ferric iron and divalent and/or monovalent metal partial salts of lower alkyl vinyl ether-maleic copolymers, which are delivered on a non-adhesive self-supporting layer(s). It is also an object of the invention to provide improved adhesive compositions which may be used with dentures and provide a firm hold and exhibit higher resistance to salivary washout.
These and other objects of the present invention will become readily apparent from the detailed description which follows.